While they were at work at this building and at the cells for the brethren, Francis explored the mountain on all its sides, to discover the sites best adapted for contemplation. He found one, where there were some large openings in the rock, great masses overhanging them, deep caverns, and frightful pits; and what seemed to him to be most curious, there was a rock so split that the interior formed a room with a smooth flooring, and a sort of ceiling which had a small opening which admitted the light. He was anxious to know whether this was the natural formation of the rock, or whether it was not the effect of an earthquake; and, after having recited the seven penitential psalms, he begged God to grant him information on this head. An angel acquainted him, in an apparition, that this had happened at the death of Jesus Christ, when the earth shook and the rocks were rent asunder. This circumstance gave Mount Alvernia additional value in the eyes of the servant of Jesus Christ crucified. He never afterwards saw these openings without thinking of the sufferings his Divine Master endured on the cross, and without wishing that his feelings of compassion might break his heart. In the opinion of the holy Fathers, the rocks which were rent when Jesus Christ expired were reproaches to the Jews for the hardness of their hearts, and this reproach falls equally on Christians who are insensible to His sufferings. We can have no difficulty in thinking, with Cardinal Baronius, that the rocks on Mount Alvernia were split at the death of our Saviour, since the earthquake was universal, according to the opinions of Eusebius, St. Jerome, and many others, and even according to the testimony of pagan authors. It is also very credible that the Son of God has manifested to His special servants, some of the effects of this motion of the earth, in order to impress more vividly on their minds the remembrance of His Passion; and may we not think that the Lord, who is the beholder of all ages, as the wise man says, and who had selected Mount Alvernia as the place in which He would do His Servant Francis the favor of imprinting the stigmata on him, as we shall see further on, was pleased to give this mountain some resemblance to that of Calvary, where St. Cyril of Jerusalem assures us, that in his time the rents caused by the earthquake were seen?